JP3451069B2 - Production and apparatus of alkylmonohydrohalosilane by redistribution reaction and then distillation - Google Patents

Description

Detailed Description of the Invention

The present invention relates to the preparation of alkyl monohydrosilanes, a starting material which has been particularly valued in organosilicon chemistry. More particularly, the present invention results from a double exchange (or redistribution) reaction of alkyl and halogen substituents between halogenated silanes that may or may not result from direct synthesis. Of these alkyl monohydrohalosilanes (AHH
S) (at least one of these silanes is a hydrosilane). This separation is carried out by distillation, the invention lies in particular in improving this step.

The present invention is particularly, but not exclusively, aimed at purifying dialkylhydrochlorosilanes produced by redistribution reactions from chlorinated alkylhydrosilanes or optionally chlorinated alkylsilanes. To do. The mono- and dialkylhydrochlorosilanes are synthetic materials of particular value in a very wide variety of applications, for example in the preparation of organosilicon monomers or more condensed base compounds.

The starting material for this redistribution reaction is obtained by direct synthesis. This technique consists of reacting an alkyl chloride with silicon in the presence of a copper catalyst to form an alkylchlorosilane. The main product of this synthesis is
It is a dialkyldichlorosilane. Other co-products are monoalkylhydrodichlorosilanes, dialkylhydrochlorosilanes, trialkylchlorosilanes and alkyltrichlorosilanes.

It would have been possible to envisage isolating the mono- and dialkylhydrochlorosilanes from the reaction mixture produced by the direct synthesis by distillation.
However, as long as the mono- and dialkylhydrochlorosilanes are minor co-products of the direct synthesis, it is clear that this method of obtaining them is not beneficial.

As a corollary, in order to produce mono- and dialkylchlorosilanes (eg Me ₂ HSiCl), according to the invention, these products are combined with alkylhydrodichlorosilanes and trialkylchlorosilanes. It would be preferable to recover from the crude mixture resulting from the redistribution reaction between the alkylhydrodichlorosilane and the tetraalkylsilane. Alkyl of silicon,
The redistribution reaction between chlorine and hydrogen substituents is carried out in the presence of a catalyst such as a Lewis acid.

In the present invention, Me is a monovalent group C
Represents H ₃ .

French patent FR-A-2,119,47
No. 7 gives a good example of this technique for the production of dialkylhydrochlorosilanes by redistribution reaction. The method disclosed in this patent uses methylhydrodichlorosilane and trimethylchlorosilane as much as 0.5 MeHSi.
It consists of reacting in the presence of a catalyst consisting of AlCl _{3 in} a molar ratio Cl ₂ / Me ₃ SiCl. The reaction mixture is placed in the reactor under autogenous pressure of 3-5 × 10 ⁵ Pa. The reaction is carried out at a temperature of 85 to 170 ° C. for several hours.
This redistribution reaction produces Me ₂ HSiCl and many by-products. When the redistribution is complete, the separation yield of Me ₂ HSiCl becomes unusually low, as it peaks at approximately 71%. Such results must be regarded as unsatisfactory with respect to industrial benefit.

To improve this situation in the industry, 19
French patent application No. 96075 dated June 12, 1996
No. 69 (still unpublished) proposed to adopt a ban on the redistribution catalyst as soon as it played its role in the reaction under consideration.
This proposal makes it possible to reduce and even eliminate the disturbing phenomenon induced by the AlCl ₃ catalyst during the redistribution reaction, ie the disproportionation reaction of the chlorinated dialkyl (methyl) hydrosilanes one wishes to purify. Let It is clear that such a disproportionation phenomenon is quite detrimental to the yield of Me ₂ HSiCl. The inhibitors provided in this improvement are polyorganosiloxanes or (poly) silanes provided in fluid or resin form and which may be alkoxylated. The catalyst metal / inhibitor oxygen molar ratio is 0.9.
It is selected within the following range of values.

These improvements made it possible to significantly increase the yield of dialkylhydrochlorosilanes.
Thus, after the redistribution reaction, interfering disproportionation is cleared, so that dialkylhydrohalosilanes (eg Me
_A distillate is obtained which consists of a mixture of redistribution reaction products rich in ( ₂ HSiCl). However, when attempting to isolate the alkylhydrohalosilane from the crude redistribution reaction mixture by distillation, a considerable loss of AHHS (Me ₂ HSiCl) is observed.

Faced with this technical problem of loss of mono- or dialkylhydrochlorosilanes during the redistribution reaction, the Applicant has set the solution as an essential objective of the present invention. Another essential aim of the present invention is to solve the above-mentioned problems and to use alkylmonohydrohalosilanes (for example Me ₂ H) which are particularly simple and economical to use.
It is to provide a method for producing SiCl or MeHSiCl ₂ ). Furthermore, another essential object of the invention is to solve the above-mentioned problems and in particular to allow alkyl monohydrohalosilanes (for example Me ₂ HSiCl) to be obtained with high levels of purity. Or MeHS
It is to provide a method for producing iCl ₂ ).

In order to be able to achieve these objects, the Applicant is specific to using a process for the preparation of alkylmonohydrochlorosilanes, and more particularly to the characteristic distillation step of this process. I realized I would prove the problem. The Applicant has found that the distillation column may use trace amounts of aluminum-containing substances, which may be aluminum chloride and / or organoaluminum compounds and / or silicon / aluminium compounds and / or organosilicon / aluminium compounds. It could be shown that it could be the site of undesired reaction of the alkyl monohydrochlorosilanes due to its presence. These traces of aluminum-containing materials (eg AlCl ₃ ) promote the conversion of redistribution reaction products to optionally chlorinated organosilane and organohydrosilane type byproducts. Thus, for example, Me ₂ HSiCl is converted to Me ₂ SiH ₂ and Me ₂ SiCl ₂ due to this disturbing disproportionation. It is clear that the latter severely interferes with this separation step of the process for producing organohydrohalosilanes (AHHS).

In addition to modernizing the technical problem, the inventive step of the present application is that it can act as a disproportionation catalyst for the latter by selecting the appropriate temperature range variable and being present in the distillation circuit with AHHS. It was supplemented and enhanced by developing conditions that consisted of quenching the compound. Naturally, the present invention relates to an industrial and economical process for preparing alkyl monohydrohalosilanes (AHHS) which are susceptible to disproportionation reactions which are contacted by at least one Lewis acid. The following essential steps are: (a) Formula (1): (R) _a (H) _{b At} least one first compound of SiX _4-ab and formula (2): (R ′) _c SiX _4-c.
A second compound (in these formulas (1) and (2),
a = 0, 1, 2 or 3, b = 1, 2 or 3, c = 1, 2, 3 or 4, a + b ≦, R
And R ′ are the same and / or different from each other and are selected from alkyl and / or aryl (preferably methyl, ethyl, propyl or phenyl), the X substituents are the same and / or different from each other, Corresponds to halogen, preferably Cl, provided that 2 of formulas (1) and (2)
A redistribution reaction with at least one X atom in at least one of the compounds of the species, said redistribution reaction being from a Lewis acid, preferably a metal halide and / or a metal borate. , More preferably AlCl ₃ ,
ZrCl ₄ , KAlCl ₄ , CuCl, H ₃ BO ₃ and BF
Performed in the presence of a catalyst selected from the group consisting of ₃ ), (b) introduction of at least one inhibitor of the redistribution reaction catalyst into the reaction mixture, (c) crude redistribution reaction mixture (a) Of the alkyl monohydrosilane formed therein, preferably including separation and collection by distillation, wherein for step (c) the crude reaction mixture is at least 1
Being subjected to a distillation process involving a base distillation column, at least a portion of the distillation circuit having formed AHH
S is behave as a redistribution catalyst with respect to this AHHS
It is characterized by being present in the presence of at least one inhibitor of the substance obtained .

An interest in the persistent inhibition of the compounds which contact the disproportionation in the distillation circuit makes it possible to obtain the target AHHS in a very pure form at the end of the distillation. The distillation at the core of the process according to the invention can be carried out batchwise or continuously using one or more distillation columns (column lines). The use of tower lines is industrially preferred. The distillation column lines used in step (C ₁ ) of the process according to the invention comprise at least 2 columns (I, II, ... N), preferably at least 3 columns.

In order to ensure the presence of the inhibitor throughout the distillation circuit, at least one injection or incorporation of the inhibitor in the circuit is carried out according to the invention. This operation, referred to herein as (C ₂ ), is, as indicated below, (i) a fluid (preferably a liquid) containing the inhibitor, while at least the first column of the distillation line. (I) the AHH
By injecting (ii) and / or the inhibitor countercurrently with respect to the fluid vapor containing S, on the other hand, into the feed fluid for the second column (II), the columns (II to N of the distillation line)
It is advantageously carried out by admixing with at least one of the (1), preferably feed fluids for column (II). According to the invention, the alternative (i) is in particular used in practice.

According to the preferred conditions of the invention, step (C
₂ ) mixes a fluid containing the target AHHS with the condensate (D _I ) produced and collected at the top of the column ( _I ) and recirculates at least a portion of this condensate R to the column (I). It is carried out by defining _I , in which case the reflux ratio r _I = R _I
/ D _I (where R _I = reflux at the top of column (I), D _I
= Distillate at the top of column (I)) is adjusted to a value of 0.5 to 3, preferably 1.5 to 2.5, more preferably about 2.

Column (I) is intended for the tailing of the fluid to be distilled, ie the removal of the redistribution catalyst (eg AlCl ₃ ) and its inhibitor (eg decamethylpentasiloxane). Column (II) contains the lightest compounds of the crude reaction mixture, ie alkyldihydrohalo (chloro), for example.
The separation of the silanes MeH ₂ SiCl and Me ₂ H ₂ Si by topping is intended. Column (III) is intended for final isolation by tailing the target alkyl monohydrosilane (eg MeH ₂ SiCl).

The AHHS one wishes to purify, the complex mixtures from which they are derived, and the equipment used, depend on the establishment of the distillation operation (number of theoretical stages, reflux ratio, column bottom and top temperatures and pressures, feed points). Is a decisive factor of.

According to a preferred form of the process according to the invention, in column (I) the crude reaction mixture is _fed with pressure parameters (P _bI , P _tI ) and temperature parameters (θ _bI , for the bottom and top of the column). θ _tI ), the number of plates n _{I and the} reflux ratio r _I are carefully fed to set the distillation fraction containing the target AHHS at the top of column (I). This fraction is then condensed into a liquid, which is separated into the reflux R _I and the distillate D _I.

The inhibitor is admixed according to alternative (i) as defined above, before or after the bypass separating on one hand D _I and on the other hand R _I , preferably before. The result is that a portion of the inhibitor will flow back into the column (II) by R _I , but a very small amount of this backflowing portion of this inhibitor is still sufficient to eliminate the disturbing disproportionation. The finding is especially surprising.

Reflux ratio r _I of the top condensate of the first column (I)
Where the reflux R _I is 60-80% by volume, preferably 70-75% by volume of the total amount of condensate formed,
It is such that it makes up 40 to 20% by volume, preferably 30 to 25% by volume, of the fraction D _I withdrawn and transferred to the next column (II).

The supply of D _I to the column (II) is carried out by distillation parameters: pressure parameters (P _bII , P _tII ) and temperature parameters (θ _bII , θ) for the bottom and top of the column.
_tII ), the number of plates n _{II and the} reflux ratio r _II , on the one hand, at the top of the column (II), an alkylhydrohalohalogen which forms a distillate (D _II ) and has a boiling point lower than that of the target AHHS. A distillation fraction containing silane and alkylsilane,
On the other hand, it is achieved by choosing to produce and collect a distillate fraction (P _II ) containing the target AHHS at the bottom of the column (II). In practice, substantially all of the gaseous fluid formed at the top of column (II) is advantageously condensed, except for the light fractions (eg MeH ₂ SiCl, Me ₂ H ₂ Si). The gas, along with the light fraction, is discharged from the distillation circuit for added value or incineration. The liquid condensate, which partially or completely, preferably completely, constitutes the balance of D _II , flows countercurrently into the top of column (II).

According to the invention, the residual liquid (P _II ) is withdrawn and transferred to the feed point of the column (III). In addition, pressure parameters for the bottom and top of the column (P _bIII ,
P _tIII ) and temperature parameters (θ _bIII , θ _tIII ), the number of plates n _{III and the} reflux ratio r _III , on the one hand, at the top of the column, a distillate consisting essentially of the target AHHS (D
_III ), on the other hand, at the bottom of the tower (II), the residual liquid (P _III )
Care was taken to set up to generate and collect a distillate fraction containing alkylhydrohalosilanes and alkylsilanes that formed and which had a boiling point above or equal to the target AHHS boiling point. In practice, the distillate D _III is preferably condensed and any impurities that may still be present (eg Me ₂ H ₂ ) can be expelled if appropriate in gaseous form.

In addition to distillation parameters, the choice of inhibitor is also a significant element of the invention. Thus, the preferred inhibitors are: • Cyclic polyorganosiloxanes (POS) containing 4 to 10 Si atoms (octamethyltetrasiloxane (D
₄ ) and decamethylpentasiloxane (D ₅ ) are preferred), • hydroxylated or non-hydroxylated linear or branched P having 2 to 100 silicon atoms
OS, more preferably polymethylsiloxane having a viscosity of 50 mPa · s, an optionally alkoxylated POS resin, an optionally alkoxylated silane, a monofunctional or polyfunctional alcohol (eg, Ethanol), ketones (eg, acetone), and mixtures thereof.

More specifically, when the inhibitor is a silicone compound, it can be: (I) a linear or substantially linear line consisting of the unit of the following formula (4), terminated at one end of the chain by the unit of formula (5) and terminated at the multi-end by the unit of formula (6): Shaped PO
S, (2i) a cyclic POS consisting of units of formula (4), (3i) a mixture of several components (1) or (2i) with each other, (4i) one or more components (i) and one Above ingredients (2
Mixture with i).

[Chemical 1] {In the above formula, the symbols R ¹ may be the same or different and may be a linear or branched C ₁ -C ₈ alkyl group which may be substituted by one or more halogen, such as methyl, ethyl, propyl. , octyl or 3,3,3; C ₅ -C ₈ cycloalkyl group such as cyclohexyl or cycloheptyl; or C ₆ -C ₁₂
Aryl or aralkyl groups having a C ₆ -C ₁₂ aryl moiety and a C ₁ -C ₄ alkyl moiety (these groups have one or more halogens, C ₁ -C ₃ alkyl and (or ) Optionally substituted by C ₁ -C ₃ alkoxy), for example phenyl, xylyl, tolyl, benzyl, phenylethyl, chlorophenyl or dichlorophenyl, the symbols Y may be the same or different and each is R Represents either ^one group or an OR ² group (R ² is a hydrogen atom or a linear or branched C ₁ -C ₃ alkyl group)}

The term "linear POS (i)" means a unit other than the units of formulas (4), (5) and (6), for example the formula: R ¹ SiO _3/2 (T) and _/ or It is to be understood as meaning a POS which does not show more than 3% of SiO ₂ (Q). The percentages given here represent the number of T and / or Q units per 100 silicon atoms.

The prohibited silicone compounds preferably have a viscosity at 25 ° C. equal to at most 1000 mPa · s, at least 60% (by number) of the symbol R ¹ representing a methyl group (i), (2i), (3i) or (4
i) Type fluid. Examples of very suitable inhibiting silicone compounds are: as linear POS (i), trimethylsiloxy units at each of the chain ends [in formulas (4), (5) and (6), R ¹ = Y = CH ₃ ] or a hydroxyl group [in formulas (4), (5) and (6) with R ¹ = CH ₃ and Y = OH], 5 to 300 m
A polydimethylsiloxane having a viscosity of Pa · s at 25 ° C., a cyclic polydimethylsiloxane having 3 to 9 units of the formula (4) (R ¹ ═CH ₃ ) as a cyclic POS (2i), And • various possible mixtures of type (3i) or (4i).

More specifically, these POSs are ・ POS1: The following formula:

[Chemical 2] A linear α, ω-dihydroxylation with a viscosity at 25 ° C. equal to 50 mPa · s and the following properties: calculated molecular weight = 283.3 g, number of oxygen atoms per mole of oil = 4.59. Polydimethylsiloxane oil, • POS2: contains 4 dimethylsiloxy units, 2 m
Cyclic polydimethylsiloxane oil having a viscosity at 25 ° C. equal to Pa · s and having the following properties: calculated molecular weight = 296 g, number of oxygen atoms per mole of oil = 4, POS3: 5 dimethylsiloxy units Including 2.
It is a cyclic polydimethylsiloxane oil having a viscosity at 25 ° C. equal to 5 mPa · s and the following properties: calculated molecular weight = 370 g, number of oxygen atoms per mole of oil = 5.

In order to define in detail other silicon compounds that can be used as the inhibitor, (i) the following formula: (R ⁰ ) _e Si (OR ² ) _4e [wherein the symbol R ⁰ is the same or different. Each may be a hydrogen atom; a linear or branched C ₁ -C ₈ alkyl group optionally substituted by one or more halogens; C _5-
C ₈ cycloalkyl group; or C ₆ -C ₁₂ an aryl group or an aralkyl group C ₆ -C ₁₂ aryl moiety and C ₁ ~
Having a C ₄ alkyl moiety (these groups may be substituted on the aromatic moiety by one or more halogens, C ₁ -C ₃ alkyl and / or C ₁ -C ₃ alkoxy); R ² may be the same or different and each represents a linear or C _{1 to} C ₄ alkyl group or a C _{6 to} C ₁₂ aryl group, and e is 0, 1, 2 or 3], 2i) A silicone resin having a viscosity at 25 ° C equal to at most 5000 mPas, with the following distinguishing features: -within its structure the formula: (R ³ ) ₃ SiO _0.5 (M),
(R ³ ) ₂ SiO (D), R ³ SiO _1.5 (T) and SiO
₂ (Q) (in these formulas, the symbols R ³ may be the same or different and predominantly has the definition given above for the symbol R ⁰ ) units (at least of these units) One is a T unit or a Q unit), and the proportion of T and / or Q units is 10%, expressed as the number of T and / or Q units per 100 silicon atoms.
Or more, and-OR ⁴ terminal group (herein, the symbol R ⁴ is carried on a silicon atom of M, D and / or T units per molecule.
May be the same or different and each is a hydrogen atom, a linear or branched C ₁ -C ₄ alkyl group or C ₆ -C ₁₂
It represents an aryl group, and the ratio of -OR ⁴ terminals is 1 silicon atom.
Expressed as the average number of these end groups per unit, 0.2 to
A compound selected from those which have the formula (between 3) are added.

In particular, these prohibited silicone compounds can be: Alkoxysilane (i) of formula (4), wherein R ⁰ is the same and each is linear or branched C ₁ -C _4.
Alkyl group or phenyl group, the symbols R ² are the same, each represents a linear or branched C ₁ -C ₃ alkyl group, and e = 1 or 2. These alkoxysilanes (i) are, for example: _{MeSi (OMe) 3 C 6 H} 5 Si (OMe) 3 (C 6 H 5) 2 Si (OMe) 2 MeSi (OC 2 H 5)
₃ C ₆ H ₅ Si (OC ₂ H ₅ ) ₃ (C ₆ H ₅ ) ₂ Si (OC ₂
H ₅ ) ₂

Resin (2i): MQ, MDQ, TD and MDT type, at most 1000 mPa · s at 25 ° C.
A resin having a viscosity of, wherein the symbols R ^{3 of the} M, D and T units may be the same or different within the structure and each represents a linear C ₁ -C ₄ alkyl group, And / or the proportion of Q units is 30% or more, -OR ⁴ terminal group (wherein the symbol R ⁴ is hydrogen or linear C
_{1 to} C ₂ alkyl group, and the ratio of the terminal groups is 0.3 to
Between 2) exists. These resins (2i) are, for example, TD type resins, and in the structure, the symbol R ^{3 of the} D unit is methyl, but the symbol R ^{3 of the} T unit is
Is an n-propyl group, the proportion of T units is in the range of 40 to 65%, expressed by the number of T units per 100 silicon atoms, and the proportion of D units is 100 silicon. Represented by the number of D units per atom, in the range of 60-35%, --OR ⁴ terminal group (wherein the group R ⁴ represents an ethyl group).
Is supported by silicon atoms of D and T units, and 0.3 to
It is as if present in a ratio between 0.5.

Quantitatively, the inhibitor is added to the distillation circuit in a proportion of at least 0.0001% by weight with respect to the amount of AHHS present in the crude reaction mixture before distillation, preferably 0.
It is preferable to mix in a ratio of 0010 to 0.0100% by weight, and more preferably 0.0020 to 0.0050% by weight.

According to another advantageous feature of the invention, the tower (II
The bottoms (P _III ) from I) is recycled by incorporating it into the feed stream of column (I). In connection with a preferred embodiment of the process according to the invention, the target AHHS is dimethylmonohydrochlorosilane and / or methylmonohydrodichlorosilane, and the three distillation columns (I, II and
III) is used. Me ₂ H in the context of this preferred embodiment
The following distillation parameters are selected for the isolation of SiCl. Column (I): Pressure (at measured bar) 0.1 ≦ P _tI ≦ 3, preferably 1 ≦ P _tI ≦ 2 0.1 ≦ P _bI ≦ 3, preferably 1 ≦ P _bI ≦ 2 · Temperature (° C. ) 60 ≤ θ _tI ≤ 120, preferably 80 ≤ θ _tI ≤ 100 90 ≤ θ _bI ≤ 150, preferably 110 ≤ θ _bI ≤ 130 ・ r _I = 2 ± 1 ・ n _I = 5 to 15 tower (II) ・Pressure (measured bar) 1 ≦ P _tII ≦ 8, preferably 4 ≦ P _tII ≦ 5 1 ≦ P _bII ≦ 8, preferably 4 ≦ P _bII ≦ 5 Temperature (° C.) 30 ≦ θ _tII ≦ 85, preferably 60 ≦ θ _tII ≦ 70 80 ≦ θ _bII ≦ 140, preferably 115 ≦ θ _bII ≦ 12
5 · r _II = 100 ± 50 · n _II = 10 to 30 tower (III) · pressure (measured bar) 10 ⁻⁴ ≦ P _tIII ≦ 1, preferably 10 ⁻³ ≦ P _tIII ≦ 10
0 × 10 ⁻³ 10 ⁻⁴ ≦ P _bIII ≦ 1, preferably 10 ⁻³ ≦ P _bIII ≦ 10
0 × 10 ⁻³ temperature (° C.) 35 ≦ θ _tIII ≦ 57, preferably 35 ≦ θ _tIII ≦ 38 63 ≦ θ _bIII ≦ 87, preferably 63 ≦ θ _bIII ≦ 66 · r _III = 20 ± 10 · n _III = 30-70

This continuous distillation using the lines of the columns (I, II and III) is well known to those skilled in the art at reflux rate, flow rate,
An arrangement for regulating pressure, boiler and condenser.

Regarding the injection of inhibitor into the circuit, the flow rate preferably used at the top of column (I) should obviously be fixed in the condensing fluid leaving column (I) and entering the second column. And depends on the amount of inhibitor you want. By way of example, for a flow rate of around 1000 g / h at the outlet of the first column, the flow rate for injection of the inhibitor is 0.1-5 g / h, preferably 0.4.
~ 1 g / h.

Thus, the process according to the invention can be carried out on an industrial scale with a purity of 90% or more, preferably 99% or more.
Or it makes it possible to obtain a dialkylhydrochlorosilane. In fact, this is a particularly attractive method for the industrial and economical production of mono- or dimethylhydrochlorosilanes.

The invention relates from another aspect to an apparatus for carrying out the method as defined above. This device
At least three distillation columns (I, II, III), the first of which is intended for tailing of the redistribution catalyst and its inhibitors, the second of which is intended for topping of alkyldihydrohalosilanes and Three intended to separate between the target AHHS and other products still present in the incoming distillation stream, and these columns contain the target AHHS
Means are provided for incorporating at least one inhibitor that is active with respect to the substance capable of contacting the side reaction in which the HHS is converted to other undesired by-products, this means of incorporation preferably being It is characterized in that it is a means for transferring the inhibitor into the condensate formed at the top of column (I).

The invention will be better understood in light of the following examples, which illustrate preferred embodiments of the device according to the invention as well as preferred embodiments of the method. A detailed description of a device according to the invention will now be given with reference to the accompanying drawings, which represent a block diagram of a preferred embodiment of the device according to the invention.

As shown in the drawing, the apparatus comprises a reactor 1 and an intermediate vessel 2 inserted between this reactor 1 and the lines of three distillation columns (I, II, III). The reactor 1 acts as a site for the redistribution stage (a). A redistribution catalyst, eg an inhibitor of AlCl ₃ , is introduced into the reactor 1 at the end of the reaction. This reactor 1 is connected to an intermediate vessel 2 by means of a pipe 3 which makes it possible to decant the first contents into the second. The crude redistribution reaction mixture thus decanted may contain some lightly volatile compounds, such as Me ₂ H ₂ Si. These volatiles produced in the vessel can be recovered in gaseous form for added value or destruction by combustion, or in liquid form after condensation. This corresponds to the outlet A in the drawing.

The reaction mixture present in the intermediate vessel 2 can then be transferred from the pipe 4 to the distillation column (I), optionally using the pump 21. The pipe 14 is connected to the column (I) at the feed point corresponding to the well-known distillation calculation (concentration stage and stripping stage). This tower (I)
Are of the type known to those skilled in the art, as are their cognate towers (II) and (III). They are columns with bubble trays, perforated trays, valve trays or any type of pile packing. Equipment tower shown in the accompanying drawings
For (I, II, III), observe that each of them exhibits a bottom and a top, between which a temperature gradient is established. At the head of each of the columns (I, II, III) there is a condensation means (5 _I , 5 _II , 5 _III ) for producing liquid or gaseous distillates (D _I , D _II , D _III ). I am meeting. Tower
At the bottom of each of the (I, II, III) is a boiler (6 _I , 6 _II , 6) suitable for providing the thermal energy needed for the change from liquid state to vapor state in the column. _III ) is provided. The condensers (5 _I , 5 _II , 5 _III ) and the boiler (6 _I , 6 _II , 6 _III ) are, on the one hand, respectively pipes (7 I
_I , 7 _II , 7 _III ), on the other hand the pipe (8 _I ,
8 _II , 8 _III ) connected to the corresponding column. The condenser 5 _I makes it possible to convert the light compound vapors from the column (I) into the liquid condensate collected in the tank 9.

The column (I) is also equipped with means 11, 12 and 13 for incorporating at least one inhibitor, preferably a cyclic polysiloxane D ₅ . These means comprise a vessel 11 for the inhibitor connected by a pipe 12 to a tank 9 for collecting the liquid condensate obtained from the toppings distillate from column (I). The pipe 12 is equipped with a flow meter 13 which makes it possible to quantitatively determine the small amount of inhibitor injected. MeH ₂ SiCl, Me ₂ H ₂ Si, Me ₂ HSi
Cl, MeH ₃ Si, Me ₄ Si, Me ₃ SiCl and M
inhibitor / liquid topping condensate mixture such comprising a compound as e ₂ SiCl ₂ is, by using the pump 14 enters the pipe 15, reflux R branches forming a pipe for the _I 1
6 and the fluid or distillate D _I is transferred to a bypass consisting of a branch 17 for feeding the column (II). The pipe 16 for the reflux appears at the top of column (I), but pipe 1
7 appears at the feed point of tower (II), which feed point is selected similarly to that of tower (I). This pipe 17 has a flow R _I
And a valve 18 is provided which makes it possible to regulate D _I. For example, one third of the flow originating from pipe 15 is transferred from pipe 17 and the remaining two thirds are reflux pipe 1
6 is transferred.

The residual liquid P _I from the column (I) is discharged from the distillation circuit via the pipe 19. The product P _I collected at this outlet is, for example, a redistribution catalyst (eg AlCl ₃ ), an inhibitor (which may be a cyclic polysiloxane, eg decamethylpentasiloxane = D ₅ ) and the heaviest heavies. Organochlorosilanes such as Me ₂ SiCl ₂ .
The vapor condensed in the liquid collected at the outlet of the condenser 5 _II associated with the top of the tower (II) is piped to this tower (I).
Backflow to the top of I). The light organosilane gas, which has not been converted to liquid by the condenser 5 _II , constitutes the distillate D _II and is discharged via the pipe 22 for the purpose of increasing its added value or being destroyed by combustion. The topping of the light product generated by the column (II) results in the formation of the liquid residual liquid P _II which is to be fed to the column (III). P _II is, for example, Me ₂ H ₂ SiCl, Me
Includes HSiCl ₂ , Me ₂ SiCl ₂ and Me ₃ SiCl.

P _II is pipe 23 (with or without a pump) at the feed point selected by using the same method as used for the feed points for columns (I) and (II). , Preferably without a pump), to the column (III). The top of column (III) is equipped with a pipe 24 for collecting the liquid condensate containing the AHHS desired to be purified. The condenser 5 _III is
It is connected to a pipe 25 for discharging the degassed product. In addition, at the top of the column (III) there is provided a pipe 26 for the reflux R _III if pure or substantially pure AHHS. At the bottom of the column (III) there is in part provided a pipe 28 for collecting the liquid P _III , which enhances the added value of the liquid and recovers it or the recovered compound (this Is, for example, Me ₃ SiC
1 and Me ₂ SiCl ₂ ) can be transported to a point for destruction.

According to another embodiment of this device, inter alia, the inhibitor injection means 11, 12 and 13 connect them to the return loop for the reflux R _I at the top of the column (I). In addition to or instead of connecting to it, it could be connected to a pipe 17 for feeding the column (II) located downstream of this loop for the reflux R _I. Also, according to another alternative, it is possible to introduce the inhibitor at the top of columns (II) and / or (III).

The process according to the invention with the lines of three distillation columns (I-III), in particular the use of the distillation stage (c), is illustrated by the various tests described below.

Example 1) Materials Used The synthesis considered in this example is that MeHSiCl ₂ and Me ₃ SiCl are redistributed in step (a) in the presence of a Lewis acid catalyst (in this case AlCl ₃ ). Synthesis of Me ₂ HSiCl (= target AHHS) produced by. This reaction takes place in reactor 1. The inhibitor used contains ₅ dimethylsiloxy units (D ₅ ),
It is a cyclic polydimethylsiloxane (PDMS) oil having a viscosity at 25 ° C. of 2.5 mPa · s and the following properties: Calculated molecular weight = 370 g Oil number of oxygen atoms per molecule = 5.

2) Equipment used The equipment as described above is used. The continuous distillation columns used (I-III) contain Sulzer-Mellapack stack packings whose height corresponds to the desired theoretical plate number. Other devices, condensers, boilers, valves, etc. are of known type.

3) Operation for step (a) 5490 g Me ₃ SiCl and 2900 g MeHS.
iCl ₂ was charged into a reactor 1 made of stainless steel, which had been previously purged with nitrogen, with stirring to obtain 0.5 MeH / Me ₃
Get the molar ratio. To this mixture is added the catalyst, 252 g of anhydrous aluminum chloride. The reactor is sealed and the pressure is adjusted to 10 × 10 ⁵ Pa with nitrogen and then to atmospheric pressure. Agitation is provided by a 4-blade turbine. The stirring speed is 100 rpm. When the reactor is heated to 100 ° C., the pressure will be established at 4.5 × 10 ⁵ Pa. The temperature is held at 100 ° C for 2 hours. 294 in the reactor
g of POS inhibiting compound is introduced in a few minutes. The combined mixture is kept at 100 ° C. for half an hour with stirring, then the reactor is cooled to 20 ° C. The residual pressure of 1.5 × 10 ₅ Pa is removed by degassing. In this way, 131
87 containing 3 g Me ₂ HSiCl and inactive catalyst
57 g of reaction mixture was obtained.

4) Step (c): 1000 g / h of the crude reaction mixture containing distilled R ₅ in column (I).
Withdraw from container 2 for feeding according to the flow rate of For continuous operation, reactor ₃ was provided with Me ₃ SiCl, MeH
10% SiCl ₂ , AlCl ₃ and cyclic PDMS D ₅
It is fed in such a way that a crude reaction mixture with D ₂ added at a flow rate of 00 g / h can be produced. The mixture thus produced is transferred to the container 2 in a batch mode. The mass balance at the inlet of column (I) (generated by gas chromatography) is as follows: 150 g / h Me ₂ HSiCl (target AHHS) 380 g / h Me ₂ SiCl ₂ 380 g / h Me ₃ SiCl 20 g / h MeHSiCl ₂ 41 g / h heavy product = D ₅ + AlCl ₃ 29 g / h Light product = Me ₂ H ₂ Si, MeH ₂ Si
Cl, Me ₄ Si and other light products total 1000 g / h

The distillation parameters of column (I) are shown below. Temperature (° C) θ _tI = 87.5, θ _bI = 116 ・ Pressure (at measured bar) P _tI = 1.5, P _bI = 1.55 ・ n _I = 10 (at the 8th theoretical stage from the bottom) Supply point) ・ r _I = R _I / D _I = 1.8 The thermal energy generated by the boiler 6 _I is 207 kca.
1 / h. 0.7 g / h of D ₅ are continuously introduced into the container 9. 0.7 g / h of these is 0.45 g / R for R _I
h and D _I are distributed at a rate of 0.25 g / h. From the analysis of P _I by gas chromatography it is possible to calculate the following flow rates at the bottom of column (I): AlCl ₃ + D ₅ ··· 41g / h Me ₂ SiCl ₂ ··· 41g / h The following substances: Me ₂ HSiCl ··· 150g / h Me ₂ SiCl ₂ ··· 339g / h Me ₃ SiCl・ ・ ・ 380 g / h MeHSiCl ₂・ ・ ・ ・ 20 g / h Light product ・ ・ ・ 29 g / h D ₅・ ・ ・ 0.25 g / h D ₂ containing 918.25 g / h in total in the column It is introduced into the pipe (II) through the pipe 17.

The distillation parameters of this column (II) are shown below. Temperature _{(℃) θ tII = 63,} θ bII = 118 · Pressure (in actual _bars) P tII = 4.4, fed at the 8th theoretical stage from _{P bII = 4.42 · n II =} 20 ( bottom Point) ・ r _II = R _II / D _II = approximately 70 Thermal energy generated by the boiler 6 _II is 102 kca
1 / h. Analysis of D _II and P _II by gas chromatography respectively shows the following results. D _II = 29 g / h, essentially MeH ₂ SiCl, Me ₂ H
₂ Includes Si and other light products. P _II = Me ₂ HSiCl ... 150 g / h Me ₂ SiCl ₂ ... 339 g / h Me ₃ SiCl .... 380 g / h MeHSiCl ₂ ... 20 g / h D ₅ ... 0 0.25 g / h In total, 889.25 g / h D _II is discharged from the gas vent 22 and P _II is introduced into the tower (III) through the pipe 23.

The distillation parameters of this column (III) are shown below.・ Temperature (° C) θ _tIII = 36, θ _bIII = 63.5 ・ Pressure (measured bar) P _tIII = 30 × 10 ^-3 , P _bIII = 35 × 10 ^-3・ n _III = 48 (27th from bottom) The feed point at the theoretical stage of r) = r _III = R _III / D _III = approximately 20 The thermal energy generated by the boiler 6 _III is 180 kc
al / h. D _III by gas chromatography
And P _III analyzes show the following results respectively. D _III = 150 g / h Me ₂ HSiCl, purity 99%
Thus, MeHSiCl ₂ is mainly contained as an impurity. P _III = Me ₃ SiCl ··· 380 g / h Me ₂ SiCl ₂ ··· 339 g / h MeHSiCl ₂ ··· 20 g / h D ₅ ··· 0.25 g / h Total 739.25 g / h h Degassing 25 does not emit Me ₂ H ₂ at all or substantially. 5) Distillation (c) without D ₅ injection is carried out at the top of the comparative column (I). D _III = Me ₂ HSiCl (75 g / h), containing 1% or more of Me ₂ H ₂ Si. Gas vents 22 and 25 are Me
A large amount of Me ₂ produced by the disturbing disproportionation of ₂ HSiCl
Let H ₂ leak. Without D ₅ injection only 50% of the Me ₂ HSiCl fed to the distillation column is recovered, whereas with D ₅ injection 100% of it is recovered. [Brief description of drawings]

FIG. 1 is a block diagram of a preferred embodiment of a device according to the present invention.

[Explanation of symbols]

1 is a reactor, and I, II and III are each three distillation columns.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Rafael Guinamarde F 69350 La Muratère, Avigne Charles de Gol, 9 (72) Inventor Francois Igerscheim F 69003 Lyon, Rum Wasone, 7 (72) ) Inventor Gilbert Margeria F 38150 Villeux-Anjou, Leer (56) References JP-A-47-13314 (JP, A) Patent 3288722 (JP, B2) (58) Fields investigated (Int.Cl. ⁷⁾ , DB name) C07F 7/12

Claims (8)

(57) [Claims] 1. The following essential steps: (A) Formula (1): (R)_a(H)_bSiX_4-abLess
Both of the first compound and the formula (2): (R ')_cSiX_4-c
A second compound (in these formulas (1) and (2),
a = 0, 1, 2 or 3 and b = 1, 2 or 3
, C = 1, 2, 3 or 4, a + b ≦ 3,
R and R'are the same and / or different from each other, and
Rukiru and / or AllieOrIs a group selected from
The X substituents are the same and / or different from each other and are halo.
GeToCorresponding, but two types of formula (1) and (2)
There is at least one X atom in at least one of the compounds
Redistribution reaction between the
Lewis acidSelectPerformed in the presence of a selected catalyst), (B) Fewer inhibitors for the redistribution reaction catalyst to the reaction mixture
Both introduced one, (C) The crude redistributed reaction mixture formed in the reaction mixture (a).
Ruquil monohydrosilaneMinutes ofSeparation and collection IncludingContact with at least one Lewis acid
Alkyl monohydrohalosilane susceptible to disproportionation reaction
In the manufacturing method of (AHHS), -For step (c), at least 1 of the crude reaction mixture
Subject to a distillation process involving a base distillation column,・ Steam At least part of the retention circuitBeen formedAHHS
Behaves as a redistribution catalyst for this AHHSShi
obtainPresent in the presence of at least one of the substance inhibitors
thing For the production of alkyl monohydrohalosilanes characterized by
Law. 2. A fluid in which the distillation step (c) essentially uses (c ₁ ) lines of at least two (I, II ... N ) distillation columns and comprises (c ₂ ) AHHS. but the flow containing the inhibitor and (i) inhibitor, on the one hand, in countercurrent direction with respect to the fluid vapor comprising the AHHS the first column (I) of at least the distillation line, on the other hand the second column (II (Ii) and / or the inhibitor by injecting it into the feed fluid for the column (II-N) of the distillation line.
By admixing with the feed fluid for at least 1 group turn)
The method of claim 1 comprising ensuring that the contact Te. 3. AH formed in step (c ₂ )
The fluid containing HS mixes the inhibitor and the latter with the condensate (D _I ) produced and collected at the top of the tower (I) and at least part of this condensate reflux R into the tower (I). By defining _I , it is ensured that they are contacted, where the reflux ratio r _I = R _I / D _I (where R _I = reflux at the top of column (I), D _I = tower). Distillate at the top of (I))
Is adjusted to a value between 0.5 and 3 . 4. In step (c ₁ ), a line of three distillation columns, each column for tailing the heavy compounds of the crude reaction mixture, a light compound of the crude reaction mixture, Tower (II) and AH for toppings
Use of a column (III) for the final separation of HS, for column (I), pressure parameters (P _bI , P _tI ) and temperature parameters (θ _bI , for the bottom and top of the column, θ _bI ,
theta _tI), the number n _I and reflux ratio r _I of the plate, is formed
Feeding the crude reaction mixture, taking care to set up so that the distillate fraction containing the recovered AHHS is recovered at the top of column (I), condensing this fraction as a liquid, The reflux R _I
And fractionating into distillates D _I , column (II), pressure parameters (P _bII , P _tII ) and temperature parameters (θ _bII , for the bottom and top of the _column ).
θ _tII ), the number of plates n _{II and the} reflux ratio r _II , on the one hand, at the top of the column (II) an alkyl which forms a distillate (D _II ) and has a boiling point lower than that of the AHHS formed. Note that the distillate fraction containing the hydrohalosilane and the alkylsilane, on the other hand, is set up to produce and collect the distillate fraction (P _II ) containing the AHHS formed at the bottom of the column (II). While feeding D _I , and to the column (III), pressure parameters (P _bIII , P _tIII ) and temperature parameters (θ _b ) for the bottom and top of the column.
_bIII , θ _tIII ), the number of plates n _{III and the} reflux ratio r
_III, on the one hand at the top of the column a distillate (D _III ) consisting essentially of the formed AHHS, and on the other hand at the bottom of the column (III) forming and forming a bottoms liquid (P _III ). Feed P _II , taking care to set up to generate and collect distillate fractions containing alkylhydrohalosilanes and alkylhalosilanes with boiling points above or equal to the boiling point of the AHHS produced. The method according to any one of claims 1 to 3, characterized in that: 5. Inhibitors are: • Cyclic polyorganosiloxanes (POS) containing from 4 to 10 Si atoms; • Hydroxylated or non-hydroxylated linear with 2 to 100 silicon atoms. Or branched P
O S 及 beauty mixtures thereof selection may POS resin be alkoxylated, it may silane be alkoxylated, - monofunctional or polyfunctional alcohols, ketones, from - and mixtures thereof The method according to claim 1, wherein the method is performed. 6. The inhibitor is at least 0.0001 with respect to the amount of AHHS present in the crude reaction mixture before distillation.
The method according to claim 1 which is selected, characterized in that it is incorporated in a proportion of weight%. 7. The AHHS formed is dimethylmonohydrochlorosilane, three distillation columns (I, II, III) are used, the following distillation parameters: column (I): pressure ( in actual _{bar) 0.1 ≦ P tI ≦ 3 0.1} ≦ P bI ≦ 3 · temperature _{(℃) 60 ≦ θ tI ≦} 12 0 90 ≦ θ bI ≦ 15 0 · r I = 2 ± 1 · n I = 5-15 column (II): · pressure (in actual _{bars) 1 ≦ P tII ≦ 8 1} ≦ P bII ≦ 8 · temperature _{(℃) 30 ≦ θ tII ≦} 8 5 80 ≦ θ bII ≦ 14 0 · r II = 100 ± 50 · n _II = 10~30 column (III): · pressure (in actual ^{_{bars) 10 -4 ≦ P tIII ≦ 1}} 10 -4 ≦ P bIII ≦ 1 · temperature _{(℃) 35 ≦ θ tIII ≦} 5 7 Write according to any one of claims 1 to 6, characterized in that _{63 ≦ θ bIII ≦ 8 7 ·} r III = 20 ± 10 · n III = 30~70 is selected . 8. At least three distillation columns (I, II, II
I), wherein the first is intended specifically for the tailing of the redistribution catalyst and its inhibitors, the second is intended for the topping of alkyldihydrohalosilanes and the third is formed.
Was AHHS and that in the distillation stream which flows are intended to separation between the still other products present, and - in these towers were formed AHHS other undesirable conversion to byproducts Are equipped with means for incorporating at least one inhibitor which is active with respect to the substances with which the side reactions mentioned can be brought into contact, these means being provided with an inhibitor at the top of column (I). 8. A method according to any of claims 1 to 7, characterized in that it is a means for transferring it into the condensate produced.